Tool grinder



June 19, 1934. YASSENOFF' 7 1,963,394

TOOL GRINDER Filed Nov. 29, 1929 2 Sheets-Sheet l 7 I'NVENTOR WWWATTORNEY June 19, 1934. YASSENOFF TOOL GRINDER Filed Nov. 29, 1929 2Sheets-Sheet 2 tax-- ATTORNEY Patented June 19, 1934 UNITED STATES.

PATENT OFFICE 30laims.

My invention relates to tool grinders and particularly to tool grindersadapted for grinding, sharpening and honing or lapping, tools havin acutting edge of very hard material, such as tungsten carbide metal. Ingrinding or sharpening such tools, there are many problems tobe overcomewhich do not exist in the case of tools made from ordinary tool steel.In the first place, tungsten carbide metal is very expensive and itbecomes essential, in grinding and sharpening tools having a cuttingedge formed from this material, to avoid grinding away more than theminimum amount of the material consistent with shaping or sharpening thecutting surface. In addition tojhis, tungsten carbide metal is very hardand the extreme hardness of the material is such that the tool tends tocut away the abrasive used to grind or sharpen it. In view of thesefacts, it has been found advisable in the grinding and sharpening ofsuch tools to use a coarse abrasive for the preliminary grinding, thento use a finer abrasive for the finish grinding, and then to hone ordiamond lapp the tool. In view of the fact that these tools may havevery irregularly shaped cutting surfaces and the necessity for threeseparate operations to grind such tools successfully, it is impossibleunder the present methods and present'machines to grind these tools insuch a way as to retain the original angularity of the cutting surfaceof the tool.

Under present methods the tool to be ground is first set up and groundon a grinder using'a coarse abrasive. This is followed by a secondoperation on a second grinder using a fine abrasive. Following this, thetool is again set up for lapping or honing on a third machine. By reasonof the fact that it is impossible to secure the same adjustment of thetool on the three separate machines in carrying out each operation, the

40 result is that the grinding produces an irregular cutting surface,which causes the tool to wear very rapidly and requires frequentregrinding. The rapid deterioration of the tools, due to the presentgrinding methods and machines, makes 5 the use of such tools veryexpensive and the three separate operations, requiring as they do threeseparate machines and adjustments of the tool to the machines, make thegrinding of these tools a most expensive operation.

An object of my invention is to provide a tool grinder which will grindor sharpen tools, having -a cutting edge of hard material, such astungsten carbide metal, with a minimum amount of loss of material in thecutting surface.

65 Another object of my invention is to provide 9. tool grinder whichwill grind or sharpen tools, having hard cutting surfaces, such as.tungsten carbide metal, with a minimum amount of we to the abrasivewheels.

Another object of my invention is to provide a tool grinder which willgrind or sharpen tools, having a cutting edge of hard material, such astungsten carbide metal, on which the rough grinding, finished grindingand lapping or honing of such tools may be carried out without thenecessity of having separate machines and separate adjustments made foreach operation.

Another object of my invention is to provide a tool grinder on whichtools having a cutting edge of hard material, such as tungsten carbidemetal, may 'be' ground, lapped or honed, without changing the angularityof the cutting surface of the tool during the three operations.

These and other various objects, features of ar-" rangement,construction and operation are plainly shown and described and will bebest understood by reference to the accompanying drawings, in which nFig. 1 is a top plan view of the assembled grinder.

Fig.2 is a side elevation of the grinder in which .the abrasive wheelsare shown cut awayland in partially in cross-section in order to showthe arrangement of the parts.

Fig. 3 is an end elevation showing more plainly 5 the arrangement of theabrasive wheels.

Figs. 4, 5, 6, 7, 8 and 9 are detailed views showing the construction ofthe tool holding jig.

Similar numerals refer to similar parts throughout the several views.

Referring to Fig. 1, an electric motor I, having a shaft 2, is rigidlymounted on a table or platform 3. On one. end of the shaft 2 are mountedabrasive wheels 4 and 5. On the other end of said shaft is mounted alapping disk 6. The 5 abrasive wheels and the lapping disk are mounteddirectly on the shaft 2 and rotate with said shaft. A lever arm '7,pivoted on a support 8, is fastened by means-of the arm 9 and bolts 10and ll to the slidable table 12, enabling it to be 10 moved backward andforward during the grinding operation. A tool holding jig 13 ismountedon a platform 14 and is adapted to be adjusted so as to present the-toolto the grinding wheels at any desired angle by reason of the universaljoint mounting 15. The platform 14 is mounted ,on a member 16 whichslidesin grooves cut in the slidable table 12. The tool holding lie 13and its platform and table may be pushed toward the abrasive wheels 4and 5 or pulled away from-said wheels by means of the screw threadedadjustment 17. When the tool holding jig platform and table are advancedtoward the abrasive wheels 4 and 5 the tool 18 to be ground is put inintimate contact with the abrasive wheels and may be carried forward andbackward across the surface of the abrasive wheels by means of theslidable table l2,-actuated by the lever 7. At the opposite end of themachine is shown the lapping wheel 6. The tool holding jig platform andtable there shown is identical in size and arrangement of parts with thetool holding jig platform and table as shown in usewith the abrasivewheels 4 and 5 and is interchangeable with the tool holding jig platformand table there shown. The

. parts on the tool holding jig platform and'table,

when used on the lapping wheel, are designated at 13a, 14a, 15a and 16arespectively. The table 16a is slidable backward and forward relative tothe lapping disk 6 precisely as the table 16 is slidable backward andforward relative to the abrasive wheels 4 and 5.

A tension spring 19 is provided which keeps the tool to be lapped 18a inintimate contact with the lapping disk at a substantially constantpressure. As shown, the tool holding jig platform and table, when usedinconnection with the lapping disk, is mounted on a slidable table so thatsaid tool 18a may be moved forward and backward across the face of thelapping disk 6.

Referring to'Fi'g. 2, the foregoing enumerated parts are shown in sideelevation. In this view, the mounting and construction of the abrasivewheels 4 and 5 is shown. The abrasive wheel 4 is constructed on a wheel21 carrying a rim 22, the wheel and rim being mounted on a collar 23,which is rigidly attached to the shaft 2 by means of the setscrew 24.Fastened to the rim 22 and the wheel 21 is a circular band of abrasivematerial 25, which surrounds the inner abrasive wheel 5 and may be ofany desired thickness as long as there remains suflicient room formounting the inner abrasive wheel 5, which is afiached to the end of theshaft 2. As shown, the shaft 2 terminates in a male screw threaded end26,- over which is fastened the female screw threaded .ex tension 27.The extension 27 carries an adjustable nut 28, which supports the innerabrasive wheel 5, and is locked in place by means of the;

nut 29. By this arrangement the inner abrasive wheel 5 may be adjustedso as to be substantially in line with the outer edge of the band ofabrasive material 25 on the abrasive wheel 4. The

- inner abrasive wheel 5 may be constructed in the manner of the usualabrasive disk butI have shown a slight modification in which a rim 30 isprovided which extends out from the surface of the wheel 5. While itisimmaterial whether the coarser abrasive wheel is the outer one or theinner one, I prefer to use a coarse abrasive substance for theconstruction of wheel 4 and a finer abrasive substance for the innerwheel 5.

As iown in this view, the base of the sliding tables 12 and 20 areconstructed with slots 31 and 32, which allow the members 33 and 34 toslide in them. This allows the tables 12 and 20 to be moved forward andbackward in order to bring the tools in contact with the entiresurfacejof the abrasive wheels 4 and 5 or of the lapping disk 6.

The end view of my tool grinder, as shown in Fig. 3, illustrates clearlythe concentric arrangement of the abrasive wheels 4 and 5. As shown inthis view, the slidable table 12 is provided with slots 35-35 in whichthe projections 36-36 of the member 16 are allowed to slide, thusallowing the tool holding jig 13 and tool 18 to be advanced toward orwithdrawn from the surface of the abrasive wheels, and also allows theremoval of the tool holding jig and tool from the slidable table 12 inorder to be inserted in the table 20 (shown in Fig. 2) when lapping thetool on the lapping disk 6, the table 20 being provided with theidentical kind of slotted arrangement as just described for the table12.

The tool holding jig 13 and the universal joint mounting 15 are shown indetail in Figs. 4, 5, 6, 7, 8 and 9. As shown in Figs. 4 and 5, a member37, in which has been placed an orifice 38 and a screw threaded orifice39, is adapted to receive a screw threaded bolt 42 (shown in Fig. 3),thus making a pivotal connection with the tool holding jig member 13. Atthe base of member 37 is an orifice 40 through which a bolt 41 (shown inFig. 3) passes and secures the member 3'7 to the member 14.

The tool holding jig member 13, as shown in Fig. 6, consists of a bodyportion 43, provided with a recessed portion 44, adapted to receive thetool to be ground, said tool being held rigidly in place by means of setscrews 45-45, which pass through the body 43 and extend into the recess44. A portion of the body 43 is cut away to an orifice 54 is provided.Rigidly mounted on the body member 48 are two extension members 49 and50. In extension member 49 is an orifice 51 adapted to receive the bolt41 (shown in Fig. 3). A screw threaded orifice 52 is provided inextension member 50 and is adapted to receive the screw threaded end ofthe bolt 41 (shown in Fig. 3). The whole member 14 is pivotallyconnected with the sliding table 16 (shown in Fig. 3) by means of thescrew threaded bolt 53 (shown in Fig. 3), which passes through theorifice 54 and into the table 16. I

While I have illustrated a preferred embodiment of my invention, manymodifications may be made without departing from the spirit of theinvention as, for example, a honing disk may .be used in place-of alapping disk when one desires to hone the tools which have been ground,

claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. A tool grinder for grinding tools having a cutting edg of tungstencarbide and including a rotatable shaft, means for rotating said shaft,abrasive wheels mounted on said shaft, a jig supporting member adjacentsaid abrasive wheels, a tool holding jig including a turntable securedto a base, a tool clamp, a universal joint connecting said turntable andsaid tool clamp, and a spring maintaining the tool in yielding intimatecontact with the abrasive wheels.

2. A tool grinder for grinding tools having a cutting edge 01' tungstencarbide and including a rotatable shaft, means for rotating said shaft,abrasive wheels mounted on said shaft, a jig supporting member adjacentsaid abrasive wheels, a tool holding jig supported by said jigsupporting member and including a turntable pivotally mounted on a base,a tool clamp. a universal joint connecting said tool clamp and saidturntable, and a spring for maintaining the tool in yielding intimatecontact with the abrasive wheels at a constant pressure.

3. In a tool grinder, the combination oi means for rough grinding toolswith means for smooth grinding of said tools, and means for lapping orhoning said tools. said grinding means and said lapping or honing meansbeing mounted on a rotatable shaft and actuated from a source 01 power,a slidabie table mounted adjacent to said

